1. Field of the Invention
The present invention generally relates image intensifier tubes and more specifically, to curved image intensifier tube components.
2. Description of Prior Art
The main component of the production model image intensifier device utilizes the intensifer tube which includes a photocathode, microchannel plate (MCP), and phosphor screen all of which are flat in cross section along the image path. With an overwhelming desire to achieve increased Field of View (FOV) for devices of this type, the optics designs become increasingly difficult, complicated, and heavy for the image intensifier device.
The maximum FOV for a typical currently fielded US military image intensifer system is 40 degrees, with full moon resolution of 0.8 cyc/mr. The next generation of imagers are anticipated to have a 60 degree FOV and full moon resolution of 1.2 cyc/mr. Optics for supporting a 60 degree FOV, with adequate exit pupil, become large (heavy), complicated, and expensive. The soldier, both airborne and dismounted, desire a Field of View more closely approximating natural vision which is about 160 degrees.
In an effort to increase the Field of View for an image intensifier system, certain optics in the system have been fabricated as curved. Coupling the curved optical space created by the objective lens to a flat intensifier faceplate has proven challenging and inefficient. Eyepiece assemblies are currently designed for a curved image plane; the prior art flat phosphor screen is coupled to a Fiber Optic Twist (FOT) with a curved surface to invert the image for proper viewing orientation and simplify the eyepiece design.
While the prior art has reported using image intensifer tube components none have established a basis for specific components that are dedicated to the task of resolving the particular problem at hand. What is needed in this instance is a modified night vision image intensifier device providing an enhanced viewable scene with greater than 60 degrees FOV.